Beckett NX Manuel D’Utilisation

RWB 6104 BNX R02

Page 13

Trained Service Technician’s Regular Maintenance

Figure 7. – Nozzle Line/Head/Air Tube As-
sembly

(Low fi ring rate shown.)

Retention Head

Head Support Legs

Electrode Tips

Electrode Clamp

Electrode Bracket

Electrode Insulator

Electrode Extension Rods

Nozzle Adapter

Nozzle

Stops in Retention Ring

Retention Ring

Throttle Ring

Throttle Cup

Nozzle Line

Bulkhead Fitting

SK9666A

Throttle Cup Hub

SK9666A

Figure 8 – Retention Head/Throttle Cup Alignment

Check Retention Head Alignment and

Cad Cell Sighting (Refer to Figure 8.)

The cad cell sighting holes in the throttle cup and

the retention head must be aligned to allow the cad
cell to detect the fl ame. Make sure the stamped key
in the retention head collar lines up with the keyway
in the nozzle adapter when mounting the retention
head. Note that in specifi c applications, the reten-
tion head may not have a sighting hole.

Check/Adjust “Zero” Calibration

On burners with factory-installed air tubes, the

zero calibration has been factory set. Make sure
the retention head (Figure 8) is securely against
the stops in the retention ring when the adjustment
plate pointer is at “0” (Figure 5).

•

If the zero calibration has not been set, perform the

following procedure:

Install the nozzle line, with the adjustment plate
assembly attached, into the burner.

Install and tighten the rear door to hold the air
adjustment plate assembly in position.

Slightly loosen the upper acorn nut, the splined
nut, and the lower acorn nut.

Turn the air adjustment screw clockwise to adjust
the plate with the pointer to the zero position.

Referring to Figure 8, slide the nozzle line as-
sembly forward until the retention head engages
the fi xed stops in the retention ring at the end of
the air tube.

Tighten the upper acorn nut securely.

The rear door must be kept tightly closed. The
adjustment screw may now be turned to adjust
the head/air setting.

Turn the adjusting screw to a setting that is 1/2
number lower than the proper set point as indi-
cated in Table 1. Then turn the adjusting screw
counterclockwise to the proper setting.

Tighten the splined nut and lower acorn nut after
the head/air setting has been adjusted.

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